this is tough... if you're on a 32-bit OS and you upgrade your video card, you're likely going to be cutting down addressable system memory. The one you currently have is only 256 mb, 9800 gt's come in 512mb and 1gb flavors. check your memory usage in performance monitor to see how much memory is being used when running all instances of wow. you should still see an fps increase from upgrading your video card, but you may also be dipping into your page file more.